Increasing oil prices and national legislation requiring the reduction of automotive carbon dioxide emissions force tire and rubber producers to produce “fuel-efficient” and thus fuel-saving tires. One approach for obtaining fuel-efficient tires lies in the production of tire formulations having reduced hysteresis loss. The hysteresis loss of a cross-linked elastomeric polymer composition is related to its tan δ value at 60° C. (see ISO 4664-1:2005; Rubber, Vulcanized or thermoplastic; Determination of dynamic properties—part 1: General guidance).
Vulcanized elastomeric polymer compositions having relatively low tan δ values at 60° C. are generally preferred for having lower hysteresis loss. In the final tire product, this translates into a lower rolling resistance and better fuel economy. In contrast, a lower tan δ value at 0° C. corresponds to a deteriorated wet grip of the tire product. Thus, it is generally accepted that a lower rolling resistance tire can be made at the expense of deteriorated wet grip properties. For example, if, in a random solution styrene-butadiene rubber (random SSBR), the polystyrene unit concentration is reduced with respect to the total polybutadiene unit concentration, the SSBR glass transition temperature is reduced and, as a result, both tan δ at 60° C. and tan δ at 0° C. are reduced, generally corresponding to improved rolling resistance and deteriorated wet grip performance of the tire. Accordingly, when assessing the rubber vulcanizate performance correctly, both tan δ at 60° C. and tan δ at 0° C. should be monitored along with the tire heat build-up.
WO 2012/091753 (Bridgestone Corp.) relates to silane-functionalized polymers and rubber vulcanizates prepared therefrom. The authors describe the use of certain alkenylaminosilanes for use in the initiation of anionic polymerizations.
US 2010/0056712 (Sumitomo Chemical Co.) relates to a conjugated diene polymer obtained by polymerizing a conjugated diene monomer and a vinylaminosilane in the presence of an alkali metal catalyst.
WO 2011/028523 (Bridgestone Corp.) relates to a process for preparing a polydiene, the process comprising the polymerization of a conjugated diene monomer with a lanthanide-based catalyst system in the presence of a vinylsilane, an allylsilane or an allylvinylsilane.
WO 2015/055252 (Trinseo Europe GmbH) relates to vinylsilane compounds which are useful as modifying monomers in the polymerization of conjugated diene monomers such as 1,3-butadiene, optionally together with an aromatic vinyl monomer such as styrene.
The present invention aims the provision of cured elastomeric polymer (rubber) compositions and means to provide such compositions, where the compositions exhibit improved tan δ values, corresponding to an improved balance of rolling resistance and wet grip performance.